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Method and device for separating formaldehyde and refining PODE2

A technology of PODE2 and formaldehyde, which is applied in the field of chemical engineering, can solve the problems of severe equipment corrosion, high energy consumption for separation, and difficult formaldehyde separation, and achieve the effect of energy saving

Active Publication Date: 2019-05-17
TIANJIN UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Over the years, domestic and foreign research teams led by BASF have done a lot of research on the synthesis and separation of PODEn, mainly reporting the route of methylal and paraformaldehyde from BASF (US 20070260094), Tsinghua University and Jade The methylal and paraformaldehyde route (CN104974025A) of Huang Chemical Co., Ltd., but because its reaction raw materials are anhydrous paraformaldehyde and paraformaldehyde, the composition of the reaction product is simple, and its separation process cannot be applied to the separation of synthetic products through other reaction routes; In addition, there is the reaction and separation process of methanol and formaldehyde aqueous solution (US 2008207954, US20080221368, US 7671240, US 7700809) of BASF Company. Limits the industrialization of its process
[0004] The route of synthesizing polyoxymethylene dimethyl ether with methanol and formaldehyde aqueous solution as the reaction system has the advantage of low raw material cost, but the difficulty of product separation limits the industrial application of this route
The azeotrope of methyl formate, methylal and methanol in the product of synthesizing polyoxymethylene dimethyl ether, PODE 3-10 It can be separated by simple distillation, but due to methanol, water, PODE 2 and formaldehyde system will form PODE 2 -Formaldehyde-Water, PODE 2 - Various complex azeotropes such as formaldehyde-methanol, so it is difficult to convert formaldehyde from PODEn product PODE 2 Separation out, refined to obtain pure PODE 2 , and formaldehyde is easily polymerized into solids during the rectification process to block the condenser and pipelines, affecting the continuity of production

Method used

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  • Method and device for separating formaldehyde and refining PODE2
  • Method and device for separating formaldehyde and refining PODE2

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Experimental program
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Effect test

Embodiment 1

[0036] Methanol, formaldehyde, water and PODE 2 The raw material of the mixture enters the first rectifying tower, and the operating pressure of the first rectifying tower is 80KPa, adopts figure 1 Feed in the same way, introduce make-up water in the middle of the first rectification tower, the mass ratio of make-up water to raw material is 0.3:1; the production fluid from the top of the first rectification tower enters the molecular sieve dehydration unit to remove water, and the molecular sieve is 3A molecular sieve The material that has dehydrated enters the second rectifying tower, and the operating pressure of the second rectifying tower is 80KPa;

[0037] After the above process, the top of the first rectification tower basically does not contain formaldehyde, and the mass fraction of formaldehyde in the formaldehyde-containing aqueous solution in the tower kettle is 42%. After cooling, there is no problem of formaldehyde polymerization blocking the pipeline, and the POD...

Embodiment 2

[0039] Methanol, formaldehyde, water and PODE 2 The raw material of the mixture enters the first rectifying tower, and the operating pressure of the first rectifying tower is 100KPa, adopts figure 1 Feed in the same way, introduce make-up water in the middle of the first rectification tower, the mass ratio of make-up water to raw material is 0.5:1; the production fluid from the top of the first rectification tower enters the membrane dehydration unit to remove water; The material enters the second rectifying tower, and the operating pressure of the second rectifying tower is 100KPa;

[0040] After the above process, the top of the first rectification tower basically does not contain formaldehyde, and the mass fraction of formaldehyde in the formaldehyde-containing aqueous solution in the tower kettle is 37%. 2 The quality fraction is greater than 99%.

Embodiment 3

[0042] Methanol, formaldehyde, water and PODE 2 The raw material of the mixture enters the first rectifying tower, and the operating pressure of the first rectifying tower is 120KPa, adopts figure 2 Feed in the same way, introduce make-up water in the middle of the first rectification tower, the mass ratio of make-up water to raw material is 1:1; the production liquid from the top of the first rectification tower enters the adsorption dehydration unit to remove water; The material enters the second rectifying tower, and the operating pressure of the second rectifying tower is 120KPa;

[0043] After the above process, the top of the first rectifying tower basically does not contain formaldehyde, and the mass fraction of formaldehyde in the formaldehyde-containing aqueous solution in the tower kettle is 20%, and there is no problem of formaldehyde polymerization blocking the pipeline after cooling, and the PODE 2 The quality fraction is greater than 99%.

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Abstract

The invention provides a method and a device for separating formaldehyde and refining PODE2. The device comprises two rectifying towers and one dehydration unit, wherein a mixture of methyl alcohol, formaldehyde, PODE2 and water enters the first rectifying tower, meanwhile water is introduced in the proper position of the first rectifying tower, a mixture of methyl alcohol, water and PODE2, not containing formaldehyde is collected from the top of the tower , a water solution containing formaldehyde is collected from a tower still, the matter collected from the tower top of the first rectifyingtower enters the second rectifying tower after being dehydrated through the dehydration unit, pure methyl alcohol is collected from the tower top of the second rectifying tower, and pure PODE2 is collected from a tower still. The method and the device effectively solve the problems that pure PODE2 cannot be obtained through rectifying because a PODE separation system contains formaldehyde and formaldehyde is gathered to block a condenser and a pipeline.

Description

technical field [0001] The invention belongs to the technical field of chemical engineering, and relates to the synthesis of polyoxymethylene dimethyl ether and the separation technology of polyoxymethylene dimethyl ether by using methanol and formaldehyde aqueous solution as reaction raw materials. 2 methods and devices. Background technique [0002] Polyoxymethylene dimethyl ether is a new type of diesel additive, the chemical formula is expressed as CH 3 O(CH 2 O)nCH 3 (Where n is greater than or equal to 1, and the value is generally less than 10), it has a relatively high oxygen content (42% to 51%) and cetane number (average up to 76), among which PODE 3-5 It is the most ideal diesel additive, adding PODE to diesel 3-5 It can effectively reduce the soot and particulate matter (PM) emissions of diesel engines and improve fuel economy. PODEn is a homologue component formed by the polycondensation reaction of the raw material that provides the end group of the ether ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C41/58C07C43/30C07C45/82C07C47/04C07C29/76C07C31/04
Inventor 李鑫钢韩振为廉景燕任远洋
Owner TIANJIN UNIV